miR-103 Promotes Neurite Outgrowth and Suppresses Cells Apoptosis by Targeting Prostaglandin-Endoperoxide Synthase 2 in Cellular Models of Alzheimer's Disease.

miR-103 has been reported to be decreased in brain of transgenic mouse model of Alzheimer's disease (AD) and in cerebrospinal fluid (CSF) of AD patients, while the detailed mechanism of its effect on AD is obscure, thus this study aimed to investigate the effect of miR-103 expression on neurite outgrowth and cells apoptosis as well as its targets in cellular models of AD. Blank mimic (NC1-mimic), miR-103 mimic, blank inhibitor (NC2-mimic) and miR-103 inhibitor plasmids were transferred into PC12 cellular AD model and Cellular AD model of cerebral cortex neurons which were established by Aß1-42 insult. Rescue experiment was subsequently performed by transferring Prostaglandin-endoperoxide synthase 2 (PTGS2) and miR-103 mimic plasmid. mRNA and protein expressions were detected by qPCR and Western Blot assays. Total neurite outgrowth was detected by microscope, cells apoptosis was determined by Hoechst/PI assay, and apoptotic markers Caspase 3 and p38 expressions were determined by Western Blot assay. In both PC12 and cerebral cortex neurons cellular AD models, miR-103 mimic increases the total neurite outgrowth compared with NC1-mimic, while miR-103 inhibitor decreases the total neurite outgrowth than NC2-inhibitor. The apoptosis rate was decreased in miR-103 mimic group than NC1-mimic group while increased in miR-103 inhibitor group than NC2-inhibitor group. PTGS2, Adisintegrin and metalloproteinase 10 (ADAM10) and neprilysin (NEP) were selected as target genes of miR-103 by bioinformatics analysis. And PTGS2 was found to be conversely regulated by miR-103 expression while ADAM10 and NEP were not affected. After transfection by PTGS2 and miR-103 mimic plasmid in PC12 cellular AD model, the total neurite growth was shortened compared with miR-103 mimic group, and cells apoptosis was enhanced which indicated PTGS2 mimic attenuated the influence of miR-103 mimic on progression of AD. In conclusion, miR-103 promotes total neurite outgrowth and inhibits cells apoptosis by targeting PTGS2 in cellular models of AD.

MAD2-p31comet axis deficiency reduces cell proliferation, migration and sensitivity of microtubule-interfering agents in glioma.

Mitotic arrest deficient-like-1 (MAD2, also known as MAD2L1) is thought to be an important spindle assembly checkpoint protein, which ensures accurate chromosome segregation and is closely associated with poor prognosis in many cancer. As a MAD2 binding protein, p31comet counteracts the function of MAD2 and leads to mitotic checkpoint silence. In this study, we explore the function of MAD2-p31comet axis in malignant glioma cells. Our results showed that disruption of MAD2-p31comet axis by MAD2 knockdown or p31comet overexpression suppressed cell proliferation, survival and migration of glioma, indicating that MAD2-p31comet axis is required for maintaining glioma cells malignancy. It is noted that MAD2 depletion or p31comet overexpression reduced the sensitivity of glioma cells to microtubule-interfering agents paclitaxel and vinblastine, providing clinical guidance for application of such drugs. Taken together, our findings suggest that MAD2-p31comet axis may serve as a potential therapeutic target for glioma.

miR-26b inhibits total neurite outgrowth, promotes cells apoptosis and downregulates neprilysin in Alzheimer's disease.

This study aimed to investigate the effect of miR-26b expression on neurites outgrowth and cells apoptosis in PC12 cellular model of Alzheimer's disease (AD). PC12 cells were stimulated by nerve growth factor and insulted by Aß1-42 to establish PC12 cellular AD model. Methyl thiazolyl tetrazolium (MTT) assay was then used to detect cells viability. Blank mimic, miR-26b mimic, blank inhibitor and miR-26b inhibitor plasmids were transferred into PC12 cellular AD models as NC1-mimic, miR-26b mimic, NC2-inhibitor and miR-26b inhibitor groups respectively. mRNA level, protein level, total neurite outgrowth and cells apoptosis were determined by qPCR, western blot, microscope and Hoechst/PI, respectively. MTT reduction rate was decreased in Aß1-42 insult group compared to control group (P<0.001). After plasmids transfection, the total neuritis growth was found to be reduced in miR-26b mimic group compared with NC1-mimic group (P<0.05) while was elevated in miR-26b inhibitor group compared with NC2-inhibitor group (P<0.01). As to cells apoptosis, the percentage of apoptosis cells was increased in miR-26b mimic group than NC1-mimic group (P<0.05), and was decreased in miR-26b inhibitor group than NC2-inhibitor group (P<0.05). In addition, neprilysin (NEP) protein and mRNA expressions were decreased in miR-26b mimic group than NC1-mimic group and was increased in miR-26b inhibitor group than NC2-inhibitor group. However, protein or mRNA expression of EIF2S1 and αTTP was not affected by miR-26b. In conclusion, miR-26b inhibits neurite outgrowth, induces cells apoptosis and downregulates NEP expression in PC12 cellular AD model.

C-myb Plays an Essential Role in the Protective Function of IGF-1 on Cytotoxicity Induced by Aß25-35 via the PI3K/Akt Pathway.

There have been numerous reports about neurodegenerative diseases, including Alzheimer's disease. Nevertheless, the molecules responsible for the neurodegeneration in Alzheimer's disease are basically unknown. Recent findings indicate that the cellular myeloblastosis (c-myb) regulates neural progenitor cell proliferation. In the current study, the function of insulin-like growth factor-1 (IGF-1) against cell toxicity in SH-SY5Y cells induced by ß-amyloid 25-35 (Aß25-35) and its molecular mechanism were investigated. It was found that p25 protein production was raised by Aß25-35 (25 µM), similar to the increased expression of µ-calpain. The results also showed that Aß25-35 reduced c-myb, elevated tau hyper-phosphorylation, and induced death of SH-SY5Y cells. Loss of cell viability and apoptosis of SH-SY5Y cells induced by Aß25-35 were attenuated by IGF-1 pretreatment in a dose-dependent manner. In addition, IGF-1 blocked µ-calpain expression, which was induced by Aß25-35 and reduced p25 formation and tau hyper-phosphorylation. Moreover, the expression of c-myb in SH-SY5Y cells was increased by combining IGF-1 with Aß25-35 or IGF-1 alone. The neuroprotective function of IGF-1 was attenuated in the SH-SY5Y cells, which were transfected with a c-myb small interfering RNA. Furthermore, LY294002, a specific PI3K inhibitor, reduced c-myb expression and abolished IGF-1's protective function in SH-SY5Y cell apoptosis induced by Aß25-35. The facts above indicate that c-myb has a role in IGF-1-mediated protection from Aß25-35-induced cytotoxicity via the PI3K/Akt pathway.